QuickChart Documentation

QuickChart Documentation

Getting Started

QuickChart is a web service that generates chart images on-the-fly. These images are suitable for embedding in email, SMS, chatbots, and other formats. Charts are rendered by Chart.js, a popular open-source charting library.

Quick Example

QuickChart works by taking Chart.js configurations and rendering them on the backend as an image. You can provide a configuration object using HTTP GET or POST requests.

For example, this simple URL: https://quickchart.io/chart?c={type:'bar',data:{labels:[2012,2013,2014,2015,2016],datasets:[{label:'Users',data:[120,60,50,180,120]}]}}

Shows this image:

QuickChart supports many types of charts and is highly customizable. Explore the documentation below to learn how to use it, jump to the chart gallery, or experiment in the live editor.

If you're stuck or running into a problem, feel free to email support or open a Github issue.

Chart API Parameters

The chart endpoint https://quickchart.io/chart accepts these query parameters:

Combine these parameters in your query string. For example: /chart?width=500&height=300&format=pdf&c={...}. If you are using Javascript or Python, you also have the option of using a client library instead of constructing the URL yourself.

Advanced API

POST endpoint

If your chart is large or complicated, you may prefer to send a POST request rather than a GET request. This avoids limitations on URL length and means you don't have to worry about URL encoding. The /chart POST endpoint takes the same parameters as above via the following JSON object:

{
"backgroundColor": "transparent",
"width": 500,
"height": 300,
"format": "png",
"chart": {...},
}

Note that if you want to include Javascript code in chart (e.g. to format labels), you'll have to send the entire chart parameter as a string rather than a JSON object. For examples, see documentation on using JS Functions.

Short URLs

You may want to create a shorter URL for your charts, especially if you are sending them via email or SMS. To generate a short URL for your chart, send a POST request to https://quickchart.io/chart/create per the above POST spec.

Here's an example using curl. You can use any library that sends an HTTP POST request:

curl -X POST \
-H 'Content-Type: application/json' \
-d '{"chart": {"type": "bar", "data": {"labels": ["Hello", "World"], "datasets": [{"label": "Foo", "data": [1, 2]}]}}}' \
https://quickchart.io/chart/create

You will get a response that looks like this:

{
"success": true,
"url": "https://quickchart.io/chart/render/9a560ba4-ab71-4d1e-89ea-ce4741e9d232"
}

Go to the url in the response to render your chart.

Note the following caveats:


Client libraries

Using QuickChart is just a matter of creating a simple URL or using an HTTP request, so a client library is not a requirement. We've released several optional client libraries for your convenience:

Javascript/Node

Run npm install quickchart-js to install the QuickChart dependency. Use it like so:

const QuickChart = require('quickchart-js');

const myChart = new QuickChart();
myChart
.setConfig({
type: 'bar',
data: { labels: ['Hello world', 'Foo bar'], datasets: [{ label: 'Foo', data: [1, 2] }] },
})
.setWidth(800)
.setHeight(400)
.setBackgroundColor('transparent');

// Print the chart URL
console.log(myChart.getUrl());

Get more details on the quickchart-js project page.

Python

Run pip install quickchart.io to install the QuickChart dependency. Use it like so:

from quickchart import QuickChart

qc = QuickChart()
qc.width = 500
qc.height = 300
qc.device_pixel_ratio = 2.0
qc.config = {
"type": "bar",
"data": {
"labels": ["Hello world", "Test"],
"datasets": [{
"label": "Foo",
"data": [1, 2]
}]
}
}

# Print the chart URL
print(qc.get_url())

See more details on the quickchart-python project page.

Chart Types

Customization can be very simple. By changing type: bar to type: line, for example, we can instantly produce an equivalent line graph:

Bar Graph

<img src="https://quickchart.io/chart?c={type:'bar',data:{labels:['January','February', 'March','April', 'May'], datasets:[{label:'Dogs',data:[50,60,70,180,190]},{label:'Cats',data:[100,200,300,400,500]}]}}">

Bar Chart documentation

Line Graph

<img src="https://quickchart.io/chart?c={type:'line',data:{labels:['January','February', 'March','April', 'May'], datasets:[{label:'Dogs', data: [50,60,70,180,190], fill:false,borderColor:'blue'},{label:'Cats', data:[100,200,300,400,500], fill:false,borderColor:'green'}]}}">

Line Chart documentation

There are many other chart types as well:

Radar Chart

<img src="https://quickchart.io/chart?c={type:'radar',data:{labels:['January','February', 'March','April', 'May'], datasets:[{label:'Dogs',data:[50,60,70,180,190]},{label:'Cats',data:[100,200,300,400,500]}]}}">

Radar Chart documentation

Pie Chart

<img src="https://quickchart.io/chart?c={type:'pie',data:{labels:['January','February', 'March','April', 'May'], datasets:[{data:[50,60,70,180,190]}]}}">

Pie Chart documentation

Doughnut Chart

<img src="https://quickchart.io/chart?c={type:'doughnut',data:{labels:['January','February','March','April','May'],datasets:[{data:[50,60,70,180,190]}]},options:{plugins:{doughnutlabel:{labels:[{text:'550',font:{size:20}},{text:'total'}]}}}}">

Doughnut Chart documentation. You can also use options from the Chart.js doughnutlabel plugin.

Scatter Plot

<img src="https://quickchart.io/chart?c={type:'scatter',data:{datasets:[{label:'Data 1',data:[{x:2,y:4},{x:3,y:3},{x:-10,y:0},{x:0,y:10},{x:10,y:5}]}]}}">

Scatter Chart documentation

Bubble Chart

<img src="https://quickchart.io/chart?c={type:'bubble',data:{datasets:[{label:'Data 1',data:[{x:1,y:4,r:9},{x:2,y:4,r:6},{x:3,y:8,r:30},{x:0,y:10,r:1},{x:10,y:5,r:5}]}]}}">

Bubble is similar to Scatter except that the r variable defines bubble radius in pixels. Bubble Chart documentation

Radial Gauge / "Meter" Charts

<img src="https://quickchart.io/chart?c={type:'radialGauge',data:{datasets:[{data:[70],backgroundColor:'green'}]}}">

View the options at chartjs-radial-gauge for customization details.

Box Plots and Violin Charts

<imgsrc="https://quickchart.io/chart?c={type:'violin', data:{labels:[2012,2013,2014,2015], datasets:[{label:'Data',data:[[12,6,3,4], [1,8,8,15],[1,1,1,2,3,5,9,8], [19,-3,18,8,5,9,9]], backgroundColor:'rgba(56,123,45,0.2)', borderColor:'rgba(56,123,45,1.9)',}]}}">

You can use violin, boxplot, horizontalBoxPlot, and horizontalViolin chart types. View the options at chartjs-chart-box-and-violin-plot for customization details. For best results, add it with a scatter plot!

Sparklines

<img src="https://quickchart.io/chart?c={type:'sparkline',data:{datasets:[{data:[140,60,274,370,199]}]}}">

A sparkline is a special case of line graph with axes and other labeling removed. All line graph options can be applied.

You can combine charts together by specifying different "types":

Mixed Charts

<img src="https://quickchart.io/chart?c={type:'bar',data:{labels:['January','February', 'March','April', 'May'], datasets:[{label:'Dogs',data:[50,60,70,180,190]},{label:'Cats',data:[100,200,300,400,500],},{type:'line',fill:false, label:'Potatoes',data:[100,400,200,400,700]}]}}">

QR codes

This web service supports QR code generation. You can render a QR code like so:

https://quickchart.io/qr?text=Here's my text

Remember the URL-encode your text parameter for more complex strings. The QR endpoint produces a PNG image by default. You may optionally set the query parameter format=svg for SVG format.

Specify the whitespace around QR image in modules with query parameter margin (defaults to 4), size in pixels of the square QR image (defaults to 150), and error correction level with ecLevel=M (valid values: L, M, Q, H).

If you'd like to customize the color of your QR code, use dark=000000 and light=ffffff. The parameters must be hex color codes. Here's the same code as above but with slimmer margins, more error protection, and colors:

https://quickchart.io/qr?text=Here's%20my%20text&dark=f00&light=0ff&ecLevel=Q&format=svg


Using Javascript functions

Simple chart configs are defined using only JSON, but more complex chart configs may include Javascript functions. QuickChart accepts charts containing Javascript.

If you're using a GET request, all you need to do is include your function in the chart definition. If you're using a POST request, make sure you send the chart parameter as a string rather than a JSON object.

Example

You may POST the following data. Note that this payload is valid JSON and the chart object is a string containing Javascript or JSON:

{
"backgroundColor": "transparent",
"width": 500,
"height": 300,
"format": "png",
"chart": "{type:'bar',data:{labels:['January','February','March','April','May'],datasets:[{label:'Dogs',data:[50,60,70,180,190]}]},options:{scales:{yAxes:[{ticks:{callback:function(value){return'$'+value;}}}]}}}"
}

Put the above JSON in a file called chart_request.json and send it via curl:

$ curl -X POST \
-H "Content-Type: application/json" \
-d @chart_request.json \
'https://quickchart.io/chart' > chart.png

Or use any other programming language's ability to send an HTTP POST request.

Building chart objects in Javascript

Below are a few Javascript examples showing how to build a chart definition containing a function:

Option 1: Build the config as a string, not an object. This is the most straightforward way.

const chartStr = `{
type: 'bar',
data: {
labels: ['January', 'February', 'March', 'April', 'May'],
datasets: [{
label: 'Dogs',
data: [ 50, 60, 70, 180, 190 ]
}]
},
options: {
scales: {
yAxes: [{
ticks: {
callback: function(value) {
return '$' + value;
}
}
}],
},
},
}
`
;

console.log(encodeURIComponent(chartStr));

Option 2: Construct your chart as a JSON object. Later, substitute your Javascript function.

const chartObj = {
type: 'bar',
data: {
labels: ['January', 'February', 'March', 'April', 'May'],
datasets: [{
label: 'Dogs',
data: [ 50, 60, 70, 180, 190 ]
}]
},
options: {
scales: {
yAxes: [{
ticks: {
callback: '',
}
}],
},
},
};

const myFormatterFunction = function(value) {
return "$" + value
};
const chartStr = JSON.stringify(chartObj).replace('""', myFormatterFunction.toString());

console.log(encodeURIComponent(chartStr));

Option 3: Serialize a normal Javascript object containing a function using javascript-stringify. This is probably the easiest to work with but it requires an external dependency.

const { stringify } = require('javascript-stringify');

const chartObj = {
type: 'bar',
data: {
labels: ['January', 'February', 'March', 'April', 'May'],
datasets: [{
label: 'Dogs',
data: [ 50, 60, 70, 180, 190 ]
}]
},
options: {
scales: {
yAxes: [{
ticks: {
callback: function(value) {
return '$' + value;
}
}
}],
},
},
};

console.log(encodeURIComponent(stringify(chartObj)));

Using Chart.js plugins and addons

QuickChart comes with several Chart.js plugins pre-installed. They are:

Use these plugins as you please in your chart config - no need to import anything extra.

Add custom plugins

As with any Chart.js chart, it's possible to add custom inline plugins by setting the plugins attribute in your chart config. Setting a custom plugins object will override the plugins built into QuickChart.

Here's an example that adds some extra space between a pie chart and its legend. Note that the global Chart object is available to the plugin:

{
"type": "pie",
"data": {
"labels": ["Yes", "No", "Maybe"],
"datasets": [{
"backgroundColor": ["#FF3784", "#36A2EB", "#4BC0C0"],
"data": [3, 24, 12]
}]
},
"plugins": [{
"beforeInit": function(chart, options) {
Chart.Legend.prototype.afterFit = function() {
// Add 50 pixels of height below the legend.
this.height = this.height + 50;
};
}
}]
}

Plugins: Annotations and Labels

In order to extend annotation and labeling capabilities beyond Chart.js defaults, we provide three additional Chart.js plugins: Data Labels (chartjs-plugin-datalabels), Annotations (chartjs-plugin-annotation), and Outlabels (chartjs-plugin-piechart-outlabels). These allow you to add various markup to your chart. Have a look at the documentation for each plugin to learn more about the possibilities.

An example of Chart.js data labels and annotations:

An example of the outlabeledPie type:


Sandbox Editor

The editor allows you to build and render a chart in real-time. Use a full-page editor here.

Try it yourself


Frequently Asked Questions

How can I make my chart look like X?

QuickChart uses the popular open-source Chart.js library, so you can use all Chart.js documentation and Chart.js-related search terms to answer questions on how to customize your chart. If you're stuck, feel free to email us.

Do I need a license to use QuickChart?

Users of QuickChart's paid versions retain full copyright to images they generate. Charts generated by QuickChart's free version are public domain.

If you'd like to fork the code, keep in mind this project is licensed under GPLv3 and you should make your code public and retain the copyright notice. If you'd like to license QuickChart privately or commercially, or if you'd like help setting up a private instance, please get in touch.

Is this a suitable replacement for Google Image Charts?

This service is a replacement for the Google Image Charts API, which turned off on March 14, 2019. QuickChart provides a drop-in replacement for Google Image Charts documented here.

QuickChart encourages the use of Chart.js format over the deprecated Google Image Charts format. Although Chart.js doesn't match exactly with the Google Image Charts API, it is a more flexible, general-purpose charting specification. Both Chart.js and QuickChart have strong open-source communities.

We encourage developers to choose a fully open-source solution over proprietary services in order to mitigate risk and future-proof their choice of API.

How reliable is QuickChart?

This site (QuickChart.io) is widely used and generates over 16 million charts per month. It is hosted on a large cluster of redundant servers. There is a built-in rate limit of 60 charts/min (1 chart/sec) per IP for free users.

If you want to adjust rate limits or need a Service-Level Agreement with uptime guarantees, purchase a license or get in touch.

See also the QuickChart status page, which monitors uptime.

How can I contribute?

QuickChart is under active development. If you'd like to suggest a feature or modify QuickChart code, please open an issue or pull request on the QuickChart Github.